Building board with acoustical foam

ABSTRACT

Disclosed is a building board construction that provides enhanced acoustical properties. In one possible embodiment, the board is a gypsum board with opposing facing sheets and an intermediate set gypsum core. An opened celled polymeric sheet is formed within the gypsum core and gives the resulting board enhanced sound absorption. In an alternative embodiment, individual pieces of polymeric foam are used in stead of the polymeric sheet. Also disclosed are various manufacturing methods whereby boards with enhanced acoustical properties can be formed in an continuous process. The various components of the present disclosure, and the manner in which they interrelate, are described in greater detail hereinafter.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of U.S. patent Ser. No. 13/837,109,filed Mar. 15, 2013, which is hereby incorporated herein by reference inits entirety.

TECHNICAL FIELD

This disclosure relates to a building board construction. Morespecifically, the present invention relates to a building board with anacoustical foam.

BACKGROUND OF THE INVENTION

Building board, also known as wallboard, plasterboard, or drywall, isone of the most commonly used building components in the world today.Building board is frequently used within the interior of a dwelling,where it functions both as a finished wall covering and as a structuralroom partition. Building board can also be used on the exterior of adwelling, where it serves as a sheathing to provide weather protectionand insulation. Building board can also be used as an interior facingfor other structures as well, such as stairwells, elevator shafts, andinterior ducting.

One particularly popular form of building board is known as gypsumboard. Gypsum board is constructed by depositing a layer of cementitiousgypsum slurry between two opposing paper liners. Gypsum slurry is thesemi-hydrous form of calcium sulfate and has many physicalcharacteristics that make it suitable for use as a building component.For example, gypsum boards generally have a smooth external surface, aconsistent thickness, and allow for the application of finishingenhancements, such as paint. Gypsum board is also desirable because itprovides a degree of fire resistance and sound abatement.

An example of a paper-covered gypsum board is disclosed in U.S. Pat. No.2,806,811 to Von Hazmburg. Von Hazmburg discloses a board that primarilyconsists of a thick gypsum core that is encased in a fibrous envelopeconsisting of both a manila sheet and a newsprint sheet. These sheetlayers can be made from a conventional multi-cylinder paper makingprocess.

Another popular form of building board is known as glass reinforcedgypsum (GRG) board. An example of one such board is disclosed in U.S.Pat. No. 4,265,979 to Baehr et. al. Baehr discloses a building boardconstructed from opposing glass fiber mats with an intermediate gypsumcore. This construction provides a hardened external surface and is animprovement over earlier paper faced boards.

Yet another type of gypsum board is disclosed in commonly owned U.S.Pat. No. 4,378,405 to Pilgrim. Pilgrim discloses a GRG board that isfaced on one or both sides with a porous, nonwoven glass mat. The glassmat of Pilgrim is fully embedded into the slurry core. This isaccomplished by vibrating the gypsum slurry to cause it to pass throughthe porous openings in the mat. Embedding the mat within the core astaught in Pilgrim results in a thin film of slurry being formed on theouter surface of the board. Building boards with this construction arereferred to as embedded glass reinforced gypsum (EGRG) boards.

These various building board constructions offer many beneficialcharacteristics. However, none of these constructions provide forincreased acoustical properties. As a result, these boards offer little,if any sound absorption or insulation, they act as a sound barrier.Sound absorption and insulation are especially important when thebuilding board is used as a room partition or even as an exteriorbuilding component. Thus, there exists a need in the art for buildingboards with increased acoustical properties. More specifically, there isa need in the art for a board that absorbs sound waves. The presentinvention is aimed at achieving these and other objectives.

SUMMARY OF THE INVENTION

The building boards of the present disclosure have several importantadvantages. In particular, the disclosed building boards provideincrease sound absorption without sacrificing any structuralcharacteristics of the board.

A further advantage is realized by providing increased acousticalproperties via the inclusion of a polymer sheet within the core of thebuilding board.

Still yet another possible advantage of the present system is achievedby incorporating a polymer sheet via a continuous manufacturing method,thereby enabling the building board of the present disclosure to bemanufactured quickly and inexpensively.

Another advantage of the present system is attained by including aseries of sound absorbing polymeric cubes within the core of thebuilding board.

Still yet another possible advantage of the present system is achievedby incorporating polymeric cubes or as a powdered material via acontinuous manufacturing method, thereby enabling the building board ofthe present disclosure to be manufactured quickly and inexpensively.

A further advantage is recognized by incorporating sound absorbingmaterials into a gypsum building board via a continuous manufacturingmethod.

Various embodiments of the invention may have none, some, or all ofthese advantages. Other technical advantages of the present inventionwill be readily apparent to one skilled in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

For a more complete understanding of the present disclosure and itsadvantages, reference is now made to the following descriptions, takenin conjunction with the accompanying drawings, in which:

FIG. 1 is a diagram of one possible manufacturing process for thebuilding boards of the present disclosure.

FIG. 2 is a diagram of another possible manufacturing process for thebuilding boards of the present disclosure.

FIG. 3 is a diagram of another possible manufacturing process for thebuilding boards of the present disclosure.

FIG. 4 is a cross sectional view of an embodiment of the building boardof the present disclosure.

FIG. 5 is a cross sectional view of an alternative embodiment of thebuilding board of the present disclosure.

FIG. 6 is a cross sectional view of an alternative embodiment of thebuilding board of the present disclosure.

DETAILED DESCRIPTION OF THE DRAWINGS

The present disclosure relates to a building board with enhancedacoustical properties. In one possible embodiment, the board is a gypsumboard with opposing facing sheets and an intermediate set gypsum core.An opened celled polymeric sheet is formed within the gypsum core andgives the resulting board enhanced sound absorption. In an alternativeembodiment, individual pieces of polymeric foam are used instead of thepolymeric sheet. Also disclosed are various manufacturing methodswhereby boards with enhanced acoustical properties can be formed in acontinuous process. The various components of the present disclosure,and the manner in which they interrelate, are described in greaterdetail hereinafter.

FIGS. 1-3 illustrate various production lines (34 a, 34 b, and 34 c) forconstructing the building boards of the present disclosure. FIGS. 4-6are cross sectional views of various board constructions (20 a, 20 b, 20c) of the present disclosure. The boards of the present disclosure aregenerally a core layer 22 of a set gypsum core and opposing paper offibrous sheets 24. In the particular embodiment illustrated in FIG. 4,board 20 a has upper and lower mats 24 which are formed from a series ofnon-woven, randomly aligned inorganic fibers. These mats are preferablyporous with interior and exterior faces. Paper facing sheets can also beused and are likewise represented by element 24.

With continuing reference to FIG. 4, upper and lower mats 24 are eachcoated with a layer of dense set slurry 26. Dense slurry 26 preferablypenetrates the upper and lower mats 24. As a result the exterior surfaceof each mat 24 is substantially covered by set slurry. Core layer 22 ofset gypsum extends fully between and bonds with the upper and lowerdense slurry layers 26. In one embodiment, core slurry layer 22 has adensity that is less than the density of the upper and lower denseslurry layers 26.

The enhanced acoustical properties are achieved via the inclusion of apolymer sheet 28 into core slurry layer 22. In the preferred embodiment,sheet 28 is formed from a melamine resin and is formed into an openedcell foam. Melamine resin is a thermoset polymer. A suitable foam isBasotect® which is manufactured and sold by BASF Corporation. Basotect®foam preferred because it provides a three-dimensional network ofslender and easily shaped webs. Basotect® foam also gives the resultingboard sound absorption, and chemical and fire resistance. However, theuse of other polymer foams is also within the scope of the presentdisclosures. For a ½ inch thick building board, a polymer sheet 28 of ⅛inch is preferred.

Sound waves entering the cells of the foam are subsequently attenuatedand dissipated, thereby giving sheet 28 its sound absorbingcharacteristics. As such, it is important that the cells of the foamremain free to gypsum slurry during the formation of the board. Polymersheet 28 is design to be positioned within, but not penetrated by, thecore slurry layer 22. Because polymer sheet 28 does not absorb theslurry layer 22, and because it preferably extends over the majority ofthe width of board 20 a, a series of apertures 32 must be formed throughthe thickness of sheet 28. Apertures 32 permit the slurry 22 to extendthrough sheet 28 to thereby fully integrate building panel 20 a. In theabsence of apertures 32, building panel 20 a would be prone toseparation along the boundary of sheet 28. In the event that polymersheet 28 could absorb slurry layer 22, apertures could be eliminated 32.In the preferred embodiment, the thickness of core layer 22 issubstantially larger than the thickness of polymer sheet 28.

FIG. 1 illustrates a gypsum board production line 34 a that has beenmodified in accordance with the present disclosure. Production lines 34a includes a series of forming tables 36 for supporting building panel20 a during its formation. As is known in the art, the mats that formpanel are under tension by way of a series of downstream belts. Oncepanel has been formed, it is passed to a series of board dryers. Dryersfunction in driving out excess moisture and causing the gypsum slurry toset. This results in the formation of a dried composite panel.

As further noted in FIG. 1, gypsum board 20 a is formed from first andsecond fibrous mats 24 which a volume of gypsum slurry being depositedfrom a mixer 38. Paper mats can alternatively be used in place offibrous mats. In either event, mats 24 are initially stored in largerolls 42 that are unwound in a continuous manufacturing method. A firstlarge roll 42 a is unwound onto forming table at location 1 a. A denseslurry layer 26 can optionally be deposited over the first mat 24 afterit is unrolled beneath a first mixer outlet 44. Rollers push the denseslurry layer through the mat at location 1 b. Additional slurry isthereafter dispensed from mixer 38 at a second mixer outlet 46 to formcore slurry layer 22. A second large roll 42 b is ideally positioneddownstream of first roll. A second mat 24 is unwound from this roll overtop of the deposited gypsum core 22 to create sandwich or panel. Theformed panel is noted at location 1 c. Mixer 38 includes a third outlet48 for supplying a dense slurry layer 26 over the second mat 24. Thepolymer sheet 28 is initially stored in a wound roll 52 and is dispensedimmediately downstream of second mixer outlet 46. This positions sheet28 in approximately the center of core 22.

An alternative production line 34 b is disclosed in FIG. 2. Line 34 b isthe same in all respects to the production line of FIG. 1; however, therolled polymer sheet 28 is replaced by a hopper 54 containing aplurality of polymer cubes 56 or a volume of a granulated polymer. Inthe preferred embodiment, cubes of approximately ½ inch are employed.Other shapes and sizes can also be used instead of ½ inch cubes.Basotect® foam can be used to produce polymer cubes 56. Cubes 56 aredispensed from a hopper 54 to a chute to deliver cubes 56 into coreslurry layer 22. In still yet additional embodiments, the Basotect® foamis added to the slurry in a grated or granular form.

The resulting building board 20 b has a cross section as illustrated inFIG. 5. Each of the polymer cubes 56 or granulated material includes anopened cell foam. Cubes 56 or granules are randomly distributed withinslurry layer 22; however, slurry 22 does not penetrate the individualpieces or cubes 56. The composite board 20 b is fully integrated as corelayer 22 extends about the individual polymer cubes 56. In still yetanother embodiment, the polymer foam can be grated to form very smallbits of foam that agglomerate into a foam fluff. This foam fluff canthen be distributed into slurry core 22.

A further embodiment of the production line 34 c is depicted in FIG. 3.This embodiment uses a polymeric sheet 28, which may have the sameconstruction as the sheet described in connection with FIG. 1. However,instead of sheet 28 being delivered into slurry core 22, it is securedto the lower mat 24 via an adhesive. More specifically, a roll 52 of thepolymeric sheet is dispensed over top of mat 24 prior to the mat beingdelivered to the forming table 36. The cross sectional view of theresulting building board 20 c is depicted in FIG. 6. As illustrated,sheet 28 is now oriented in facing relation with the first mat 24. It isalso within the scope of the present invention to apply sheet 28directly to one of the upper or lower dense slurry layers. This wouldavoid sheet 28 being secured to mat 24. Either of these embodiments maybe used in connection with either of the previously describedembodiments.

Although this disclosure has been described in terms of certainembodiments and generally associated methods, alterations andpermutations of these embodiments and methods will be apparent to thoseskilled in the art. Accordingly, the above description of exampleembodiments does not define or constrain this disclosure. Other changes,substitutions, and alterations are also possible without departing fromthe spirit and scope of this disclosure.

What is claimed is:
 1. A method for making a composite, multi-layeredbuilding panel with enhanced acoustical properties, the panelcomprising: opposed upper and lower mats, the opposed upper and lowermats having interior and exterior faces; a core layer of set gypsumhaving a thickness extending between the upper and lower mats; and apolymer sheet positioned within the core layer such that the set gypsumof the core layer contacts both upper and lower surfaces of the polymersheet, the polymer sheet having a thickness less than the thickness ofthe core layer, the polymer sheet having sound-absorbingcharacteristics; the method comprising providing the polymer sheet woundon a first roll; providing the lower mat wound on a second roll;continuously unwinding the lower mat from the second roll onto a formingtable and moving the lower mat along the forming table in a firstdirection; in a first zone continuously forming a core slurry layer onthe lower mat and continuously unwinding the polymer sheet from thefirst roll thereof and continuously disposing the polymer sheetcentrally within the core slurry layer; providing the upper mat wound ona third roll; continuously unwinding the upper mat from the third rolland disposing the upper mat on the core slurry layer having the polymersheet disposed within; and after disposing the upper mat thereon,causing the core slurry layer to set.
 2. The method according to claim1, wherein the core layer of set gypsum extends through the polymersheet.
 3. The method according to claim 1, wherein a series of aperturesis formed through the thickness of the polymer sheet, the core layerextending through the apertures to allow the polymer sheet to bond tothe core layer.
 4. The method according to claim 1, wherein the polymersheet is formed from a thermoset polymer.
 5. The method according toclaim 1, wherein the polymer sheet is formed from a melamine resin. 6.The method according to claim 5, wherein the polymer sheet has an opencell structure, the open cell structure enhancing the sound-absorbingcharacteristic of the building panel.
 7. The method according to claim1, wherein the polymer sheet has an open cell structure, the open cellstructure enhancing the sound-absorbing characteristic of the buildingpanel.
 8. The method according to claim 1, wherein the compositebuilding panel further comprises an upper layer of a set slurry coatingthe upper mat, and a lower layers of a set slurry coating the lower mat,wherein the upper and lower layers of set slurry have a greater densitythan the core layer, and wherein the lower mat is provided with denseslurry layer formed thereon; the core slurry layer continuously isformed on the dense slurry layer of the lower mat; the upper mat isprovided with a dense slurry layer formed thereon; and the upper mat iscontinuously disposed on the core slurry layer with the dense slurrylayer thereof against the core slurry layer.
 9. The method according toclaim 8, wherein the set gypsum of the core layer extends from the upperset slurry coating layer to the lower set slurry coating layer.
 10. Themethod according to claim 8, wherein the upper and lower mats are porousmats formed from non-woven, randomly aligned inorganic fibers, whereinthe upper and lower set slurry coating layers penetrate the upper andlower mats.
 11. The method according to in claim 1, wherein the setgypsum of the core layer extends continuously from the upper mat to thelower mat.
 12. The method according to claim 1, wherein the upper andlower mats are porous mats formed from non-woven, randomly alignedinorganic fibers.
 13. The method according to claim 1, wherein the upperand lower mats are paper sheets.